A turning tool holder is arranged to hold a cutting tool insert. The turning tool holder, including the cutting tool inset, is used in a machine tool such as a lathe for machining of a workpiece. Turning tool holders of many different configurations, and adapted to be used with cutting tool inserts of many different geometries are known. Namely, depending on what kind of turning operation is to be performed on a workpiece, the turning tool holder must be able to reach a relevant portion of the workpiece and the cutting tool insert must have a suitable geometry.
A cutting tool insert is commonly provided with two or more cutting edges. Thus, the cutting tool insert may be placed in two or more different positions in a relevant turning tool holder to expose one of the cutting edges at a time to engage with a relevant workpiece. Put differently, the cutting tool insert is indexable the same number of times as there are cutting edges.
Coolant, also referred to as cooling liquid or a cooling fluid, may be distributed to a cutting zone of a workpiece. Commonly the coolant is a liquid but gas, such as air, may be used as a coolant in some cutting applications. Traditionally, for this purpose a lathe may be provided with a separate nozzle adapted to be directed towards a workpiece. A more modern approach is to provide one or more nozzles for coolant integrated in a turning tool holder. Thus, the nozzle(s) may be arranged in close vicinity of a cutting zone of a workpiece. Nozzles for coolant may be provided in a turning tool holder at a rake face side and/or a relief face side of a cutting edge of a cutting tool insert.
U.S. Pat. No. 8,454,274 discloses an indexable cutting insert comprising a coolant delivery trough, which has a radial orientation toward a corresponding corner cutting region. With reference to FIGS. 5-7 the document discloses a shim arranged below the cutting insert. A coolant passage is provided in the shim and a coolant outlet is formed between the cutting insert and the shim.
In such a prior art arrangement, i.e., a jet of coolant from the coolant outlet, is influenced by both the shim and the cutting insert. Accordingly, if a relevant corner cutting region of the cutting insert is worn from prior use and then positioned to form the coolant outlet together with the shim, the jet of coolant from the coolant outlet may differ depending on the wear of the cutting insert.